Two terms that students often confuse in statistics are **outcome** and **event**.

Here’s the subtle difference between the two terms:

**Outcome:** The result of a random experiment.

- For example, there are six potential outcomes when rolling a die: 1, 2, 3, 4, 5, or 6.

**Event:** A set of outcomes that has a probability assigned to it.

- For example, one possible “event” could be rolling an even number. The probability that this event occurs is 1/2.

The following examples show more scenarios that illustrate the difference between outcomes and events.

**Example 1: Deck of Cards**

Suppose we randomly draw a card from a standard deck of 52 cards.

The four possible **outcomes** for the suit of the card include:

- Heart
- Spade
- Diamond
- Club

One of these four outcomes must occur.

However, there are many different **events** that we may be interested in assigning a probability to. For example:

**Event 1: Draw a Heart**

- The probability that this event occurs is 13/52 or 1/4.

**Event 2: Draw a Heart or a Spade**

- The probability that this event occurs is 26/52 or 1/2.

**Event 3: Draw a card that is not a Heart**

- The probability that this event occurs is 39/52 or 3/4.

There are many more events that we could come up with and assign a probability to, but these are just three simple ones.

**Example 2: Pulling Marbles from a Bag**

Suppose a bag has 3 red marbles, 5 green marbles, and 2 blue marbles.

If we close our eyes and randomly select one marble from the bag, the three possible **outcomes** for the color of the marble include:

- Red
- Green
- Blue

One of these four outcomes must occur.

However, there are many different **events** that we may be interested in assigning a probability to. For example:

**Event 1: Draw a Blue Marble**

- The probability that this event occurs is 2/10 or 1/5.

**Event 2: Draw a Blue or Green Marble**

- The probability that this event occurs is 7/10.

**Event 3: Draw a Marble that is not Blue**

- The probability that this event occurs is 8/10 or 4/5.

These are three events that we can easily calculate probabilities for.

**Additional Resources**

How to Find the Probability of “At Least One” Success

How to Find the Probability of A or B

How to Find the Probability of A and B

Small typo in Example 2. After listing the three color outcomes for the marble it accidentally states “One of these *four* outcomes must occur.”